The present invention is directed to an improvement in a strapping machine. More particularly, the present invention is directed to a strapping machine having an automatic strap clearing and reloading assembly for severing and clearing misfed strap from between the infeed wheels and the strapping head and for refeeding the strap into the infeed wheels.
Strapping machines are in widespread use for securing straps around loads. One type of known strapper is a stationary unit that includes a strapping head and drive mechanism mounted within a frame. A chute is mounted to the frame, through which the strapping material is fed. In a typical arrangement, a table-top or work surface is likewise mounted to the frame.
In a typical stationary strapper, the chute is mounted from about the work surface, and the strapping head is mounted below the work surface. Strap is fed from a source or dispenser to the strapping or welding head. The strapping head provides a number of functions. First, it includes a plurality of grippers for gripping portions of the strap during the course of a strapping operation. The strapping head also includes a cutter to cut the strap from a strap source or supply. Last, the strapping head includes a sealer to seal an overlying course of strapping material onto itself. This seal is commonly referred to as a weld and is effected by heating overlying courses of the strap by use of a vibrating element.
Strapping material is fed from the dispenser into the strapping head first via a pair of infeed wheels and second via a feed assembly. The infeed wheels are typically located immediately inside of the strapping machine (e.g., inside of an enclosure or cabinet). The infeed wheels facilitate smoothly feeding the strapping material into the strapper and further supply strapping material into the slack box. The slack box is an area between the infeed wheels and the strapping head that is used to store a length of “slack” strapping material for use by the strapping head and is also an area for storing take-up strap that has been rewound or tensioned around the load.
In that many strapping operations are generally ancillary to some other operation, such as a manufacturing operation, it is desirable to maintain the strapping operation as a fully or semi-automated process. To this end, it is also desirable to have any malfunctions, misfeeds and the like self-corrected by the strapping machine.
One known strapping machine includes a strapping head that serves a dual function that includes, beyond the typical strap sealing and severing operations, that of ejecting misfed strap and refeeding strap material into the strapping head. Such an arrangement is disclosed in Bell et al., U.S. Pat. No. 5,640,899, which patent is commonly assigned with the present application and is incorporated herein by reference.
Unfortunately, the arrangement disclosed in the aforementioned patent to Bell et al., serves only to eject misfed strap from the strap path from the strapping head, around the strap chute and back to the strapping head. Misfed strap prior to the strapping head (e.g., between the dispenser and the strapping head), must be manually pulled from the machine, as by an operator, and refed to the strapping machine.
Accordingly, there is a need for a strapping machine having an automatic strap clearing and reloading assembly. Desirably, such a clearing and reloading assembly severs and clears misfed strap from between the infeed wheels and the strapping head and refeeds the strap into the infeed wheels. Most desirably, such an assembly directs that ejected strap away from the strap path so that reloading is readily accomplished without interference.